#include <REGX52.H>
void Delay(unsigned int xms);
unsigned char LEDNum;
void main()
{
	P2 = ~(0x01);
	while(1)
	{
		if(P3_0 == 0)
		{
			Delay(20);
			while(P3_0 == 0);
			Delay(20);
			LEDNum++;
			if(LEDNum >= 8)
				LEDNum = 0;
			P2 = ~(0x01<<LEDNum);
		}
		if (P3_1 == 0)
		{
			Delay(20);
			while(P3_1 == 0);
			Delay(20);
			if(LEDNum == 0)
				LEDNum = 7;
			else
				LEDNum --;
			P2 = ~(0x01<<LEDNum);
		}
		
	}

}


void Delay(unsigned int xms)		//@12.000MHz
{
	unsigned char i, j;
	while(xms)
	{
		xms--;
		i = 12;
		j = 169;
		do
		{
			while (--j);
		} while (--i);
	}
}